It is often useful to recover the image that was originally printed on a hardcopy document later became altered or damaged. For example, it is often difficult to recreate information that is printed on financial, legal, medical and government, but it is essential that those who rely upon these types of information to know that the information they receive is accurate and complete. Thus, it would be beneficial to provide a way to view the original version of an image that is presented on a printed document, to confirm it accuracy and when necessary, to recover data from a document that has been damaged.
Known image processing methods use “glyphs,” i.e., graphical indicia that are used to encode digital information, to print duplicated versions of a digital image on a single document. Unfortunately, glyphs are highly visible and thus, they often detract from the visual appearance of the document. Magnetic inks, gloss marks and other substances that are much less visible are also available, but the costs of providing the equipment that is required to capture the data often renders the use of those substances impractical.
Available software programs can highlight changes in electronic versions of a modified image for comparison purposes. Those programs cannot, however, identify and highlight changes that are made to printed data. It is also relatively easy to deliver editing history with electronically stored documents. Unfortunately that information is lost when the document is printed, even if the hardcopy document is scanned and the image is returned to electronic storage.
Accordingly, it would be advantageous to be able to redundantly encode image data on a hardcopy document, to do so without altering the visual appearance of the document and to enable the redundant versions of the image to maintain their association as the hardcopy document is digitally captured, processed and printed.